Conventionally, there has been proposed an ink ribbon for a thermal transfer printer having a thermal head that allows formation of print images on various printing media in cases from low-speed printing where printing energy is high to high-speed printing where printing energy is low, as disclosed, for instance, in Japanese Patent No. 3025311.
In a conventional ink ribbon as in the above, a thermoplastic adhesive layer with film forming properties is formed on a surface of a coloring layer having a waxy material as the major component of a vehicle thereof, so as to form a thermal transfer layer, and a material with supercooling properties is used for the adhesive layer, so that it is made possible to lengthen a duration maintaining a state in which the adhesive layer melts and softens to exhibit high adhesive force, and to form a print image on various printing media.
However, if the duration maintaining the state in which the adhesive layer melts and softens to exhibit the high adhesive force is lengthened as in the above-mentioned ink ribbon, even though the print image can be formed on the various printing media, the possibility of reverse transfer of the print image onto the ink ribbon side becomes high due to the longer duration of melting and softening of the adhesive layer.
Thus, if a print image is reverse-transferred onto the ink ribbon side, an ink void occurs in the print image on a printing medium, thus inhibiting a clear print image.